Through the present application, “nX antenna” is named from a type of an electrical charge flow depending on the structural characteristics of antennas disclosed by the present invention.
Due to rapid developments in the analog and digital communication technologies worldwide at the present, mobile communication services, such as cellular, PCS, GSM, PHS, the former Iridium service using an artificial satellite, IMT2000 service, etc., are being provided. Also, wireless communication is being used in various fields, such as wireless LAN, radios, wireless communication between apparatuses positioned within a local area, and wireless communication fields are being widely spread.
For instance, the mobile communication terminal antenna mainly uses a nondirectional retractable antenna owing to requirements of bi-directional communications are possible and it is easy to carry the antenna. Antennas of terminals that are being sold are a combination type in which an antenna suitable for a signal standby state, and an antenna suitable for telephoning state are combined, and antennas capable of transmitting and receiving linear polarization signals easily are used.
The antenna type, which protrudes upward from the terminal, mainly employs a combination type in which a spring shaped helical antenna extends and a monopole shaped whip antenna, which extends upward to enhance communication quality, are combined. In other words, in the mobile terminals, such as mobile phones, radios, PCS, etc., for performing wireless communication between moving terminals, or between a moving terminal and a fixed place, the antennas use a combination of a whip antenna and a helical antenna.
FIG. 1 is a schematic view of a conventional helical-whip combination type antenna. With reference to FIG. 1, the conventional helical-whip combination type antenna is described. The basic structure includes a helical antenna 2 and a whip antenna 3. The helical antenna 2 has a spiral conductor of a length of approximately λ/4. The whip antenna has a monopole shape. In a signal standby state or when the surrounding environment is good, the helical antenna 2 alone operates, and at a place where the electromagnetic wave environment is bad, the two antennas 2 and 3 operate at the same time in a state where the whip antenna 3 extends from a main body 1. The antennas are classified depending on positions of the helical antenna 2, and there are many modifications depending on the feed and combination of the two antennas. Antennas for mobile communication terminals, having a structure in which the helical antenna 2 is coupled to one end of the whip antenna 3, are being used as representative antennas for foreign PCS terminal products and local products. Representative of these antennas are products made by Allgon company in Sweden, which manufactures antennas. A structure, in which the helical antenna is coupled to the main body of the terminal, has a lower feeding point of the helical antenna and the whip antenna connected to the same metal connector 4. Motorola, Inc. manufactured an antenna having the same basic structure as the product of Allgon Company but used a different feeding method, and used the antenna in some terminal models. In an early stage, Korean cellular terminal models mostly used products of Allgon Company.
However, since this conventional mobile communication antenna is made as a structure protruding from the terminal, the antenna may be broken by an external force. Also, in a case when a user moves while putting the terminal in a pocket, the antenna becomes caught by a portion of the pocket causing an inconvenience in the use of the terminal.
Also, since the antenna has a minimum size due to the frequencies used characteristic in the above structure, although the terminal size may decrease, the antenna size may not decrease. Also, the area occupied by the antenna becomes larger.
Further, owing to the limitation in the performance of the antenna, the conventional antenna has the largest disadvantage involving communication quality, such as noise, cut off in calling, etc.
FIGS. 2A and 2B are sectional views of improved antennas in accordance with a conventional art. In order to overcome the aforesaid disadvantages, proposed conventional built-in antennas 10 and 20 for a mobile phone, as shown in FIGS. 2A and 2B, include, respectively, first body parts 11 and 21, second body parts 12 and 22, spaces 13 and 23 and antenna rods 14 and 24. The first body parts 11 and 21 and the second body parts 12 and 22 are made of a conductor, and have sealed upper faces and side faces and openings without a lower face. Diameters and lengths of the first body parts 11 and 21 and the second body parts 12 and 22 are decided depending on transmission and reception frequency band and their gains. The antenna rods 14 and 24 are made of a conductor, and are inwardly coupled to the upper faces of the first body parts 11 and 21 and the second body parts 12 and 22 to be connected to each other and fixed. The spacers 13 and 23 are made of nonconductor, and are coupled to the openings of the first body parts 11 and 21 and the second body parts 12 and 22 to maintain intervals between the first body part 11 and the second body part 12 and between the first body part 21 and the second body part 22. The antennas can be set by finely controlling the spacing between the first body part 11 and the second body part 12 and between the first body part 21 and the second body part 22, where the spacers 13 and 23 are positioned.
Here, the conventional dipole antenna includes an anode and a cathode. Generally, grounding of the substrate itself or a cathode pattern formed on the substrate is used as the cathode, and an antenna structure itself is used as the anode. In describing the present invention, the anode is referred to and the antenna, and descriptions of the matching circuit and other circuits are omitted.
The antennas 10 and 20 are installed at the outside of the substrate. An antenna connector is electrically connected to an antenna circuit part on the substrate, and is installed on the substrate. In the dipole antenna, the antennas 10 and 20 are used as the anode, and a circuit substrate is used as the cathode. Instead of the circuit substrate, a cathode separately formed on the substrate can be used. This antenna is made such that it is located within the case of the mobile phone. The cathode associated with the anode of antennas 10 and 20, is a conductive pattern or an antenna structure having the same structure as the anode can be used.
Thus, in the antenna structure including the first body part 11 and 21, the second body parts 12 and 22, the spacers 13 and 23 and the antenna rods 14 and 24, phase inversion is repeated by an electric flow pattern on the surface and thus resonance is generated, so that a desired gain and frequency characteristic can be obtained by using an antenna having a short length in a structure and appearance.
These antennas can be installed at any position out of the left side, right side, upper side and lower side. The cathode can be formed in a conductive pattern on the substrate to be matched with the anode. Two antennas having the same structure can be installed and connected respectively to the cathode and the anode. The two antennas can be installed in parallel to each other, or installed separately from each other in vertical direction and horizontal direction.
Then, in the foregoing antenna structure, when the two body parts are coupled such that their grooves face with each other, if a spacer of a nonconductor is formed as an interval maintaining hole and the antenna rod is coupled to both ends of the body parts using a screw or a stepped portion, the number of the elements becomes large. Since the antenna rod should be made longer to be coupled to the inside of the groove, the volume of the structure becomes large, increasing the use of raw material, weight, assembly time increases, workability is lowered, and manufacturing cost is increased.
Also, in the antenna structure, since the antenna is installed in a state in which the both ends are closed, there exists a drawback in which application width is limited in a structure connecting and installing the antenna to the circuit part of the substrate.